Human History Written in Stone and Blood

In the past decade it has become clear that symbolic expression associated with modern human behavior began in Africa, not Europe. And it occurred tens of thousands of years earlier than was once thought. Answering why is difficult. A first step was more reliable dating of when culturally and technologically advanced people lived during the Middle Stone Age in the south of Africa. Zenobia Jacobs and Richard G. Roberts accomplished that dating, which prompted them to reject climate change as a primary cause for the advancements. Instead, drawing on genetic research, they embrace population growth as a likely, key influence.